What Is Primary Myelofibrosis (PMF)?
- Primary Myelofibrosis (PMF) is a rare type of blood cancer in which scar tissues build up in your bone marrow, making it difficult for the bone marrow to produce enough healthy cells.
- In the early stages of PMF, you may not have any symptoms; a routine blood test at your doctor’s office may show abnormalities in your hemoglobin, white blood cells and/or platelets.
- Your doctor can treat PMF in several ways and these options are selected based on age, symptoms, presence of mutations, and your overall health status.
As scar tissue formation increases, the bone marrow cannot make enough healthy blood cells. Bone marrow is the spongy tissue inside large bones where white blood cells, red blood cells, and platelets are made from specialized stem cells. These blood cells are then released into your blood to travel throughout the body performing various critical functions:
- Red blood cells deliver oxygen to the body
- White blood cells help in fighting off infections
- Platelets allow the body to form clots to stop bleeding
What is Primary Myelofibrosis (PMF)?PMF is a type of cancer that falls under the category of myeloproliferative neoplasms (MPNs). “Myelofibrosis is when your bone marrow is making too many fiber cells and preventing the bone marrow from making normal blood cells,” Dr. Adrienne Phillips, a hematologist/medical oncologist at Weill Cornell Medicine, tells SurvivorNet.
PMF develops when an error happens in the JAK2, CALR, or MPL genes of your bone marrow cells.
“Even though these mutations (JAK2, CALR, or MPL) are really common across other MPNs, they have a very different clinical course that can evolve over time and change from potentially one subtype to another,” explains Dr. Ghaith Abu-Zeinah, a hematologist/medical oncologist at Weill Cornell Medicine.
Dr. Abu-Zeniah explains that the proliferative process is “significantly increased and more aggressive” in myelofibrosis than some of the other myeloproliferative neoplasms.
“And that kind of proliferative type of disease can really over time, lead to significant amount of inflammation and really lead to a sort of a bone marrow burnout where the bone marrow is struggling to make a enough blood cells for us to survive normally,” Dr. Abu-Zeniah says.
PMF can run in multiple members of your family. It affects middle-aged and older adults.
What Are The Symptoms?
In the early stages of PMF, you may not have any symptoms; a routine blood test at your doctor’s office may show abnormalities in your hemoglobin, white blood cells, and/or platelets. Later in the course of the disease, you may feel a dull pain in the belly as your spleen grows, have night sweats, or feel more tired than usual. Increasing symptoms can sometimes be a sign of the disease becoming more aggressive.
In general, the common symptoms include:
- You may feel more weak and tired than usual, you may also develop shortness of breath or pale skin color due to anemia (low red blood cell count)
- Frequent infections due to a low white blood cell count and low immunity
- Bleeding or bruising easily due to a low platelet count
- Abdominal pain and fullness of the belly as a result of an enlarged spleen
- Weight loss, sweating at night, low-grade fever
- Bone or joint pain
How is PMF Diagnosed?
Based on your symptoms and a medical examination, your doctor will arrange blood tests and a referral to a hematologist. Your doctor will come to a diagnosis based on the results of the following tests:
- Complete blood count (CBC): This routine blood test checks the levels of hemoglobin, different types of white blood cells, and platelets. In PMF, your routine blood test may show anemia and abnormal counts of white blood cells and platelets. Higher counts of white blood cells and platelets are usually found in the early stage of the disease, but low numbers of these cells are common in more advanced stages. Your red blood cells may look ‘teardrop-shaped’ under the microscope.
- Bone marrow biopsy: A bone marrow examination may be needed in some patients to confirm the diagnosis. Your doctor takes a small sample of your bone marrow, usually from the hip bone. Then the pathologist looks at the cells under a microscope to determine cancer, presence of mutation, and/or chromosomal abnormality on the cancer cells.
How is Primary Myelofibrosis (PMF) Treated?
Your doctor can treat PMF in several ways, and these options are selected based on age, symptoms, presence of mutations, and your overall health status. Sometimes symptoms may not be present for many years and your PMF may only require monitoring. The available treatment options for PMF are:
- Ruxolitinib (Jakafi): This is the first drug approved by the Food and Drug Administration (FDA) for the treatment of PMF. It is an oral medication that targets and blocks the common genetic mutation in PMF, which is called a JAK2 mutation. “JAK2 mutation is one of the main drivers of this disease, but even the patients with PMF who have CALR or MPL mutations would benefit from JAK2 inhibitors,” Dr. Abu-Zeinah explains. These medications can significantly improve the symptom burden including decreasing the size of the spleen. If ruxolitinib causes too many side effects such as nausea, vomiting, diarrhea, leg ulcers, flu-like symptoms, bone pain or loss of appetite, your doctor may instead prescribe Fedratinib (Inrebic) which is also an oral JAK2 blocking medication. It also reduces PMF-related symptoms, but there is a risk of thiamine deficiency leading to serious neurological complications. Your doctor will check your thiamine level periodically during treatment.
- Anagrelide (Agrylin) or Interferon alfa-2b (Intron A): The medication is taken orally. It helps to relieve some of the symptoms associated with the PMF, including enlargement of the spleen, night sweats, itching, weight loss, and fever.
- Bone marrow transplant: This is the only option that can potentially cure your PMF. It is a medical procedure during which cells from a healthy bone marrow donor are transplanted into your bone marrow or your blood. This procedure can be risky for older patients and those with other medical problems. Your doctor will determine if you are a candidate for a bone marrow transplant.
For most patients, the goal is to help with the disease symptoms and complications, enhance your quality of life, and make you live longer. In PMF, blood transfusions are considered a form of supportive care to try to improve the symptoms related to anemia and prevent some of the complications that could arise with this disease. During a blood transfusion healthy donor blood is infused into the PMF patient via an IV.
Sometimes your doctor may prescribe hydroxyurea when other medications fail to reduce the size of the spleen. Hydroxyurea is an oral chemotherapy medication that decreases the white blood cells and platelets produced by your bone marrow and thereby decreases your symptoms. You may experience nausea, vomiting, diarrhea, leg ulcers, flu-like symptoms, bone pain, and loss of appetite with hydroxyurea.
Rarely, radiation to your spleen or removal of the spleen (splenectomy) may also be needed in severe cases.
It is important to have regular follow-ups, and blood tests, and discuss with your doctor any side effects during treatment. You might need additional bone marrow biopsies during the disease course.
For some patients with PMF, the current treatment options may not work or may cause too many side effects. In that case, clinical trials may be an appropriate option. Your doctor can make this assessment and guide you in the enrollment of clinical trials.
Questions To Ask Your Doctor
- What are the options for treating my PMF?
- How do we monitor to ensure my PMF is improving?
- Are there clinical trials that can help treat my PMF?